monitors: draw a scale being typed at 1

The page binds the canvas to size(), and an empty or partial scale gave
Infinity or NaN and broke the fit. Apply is still held back until the
scale is a positive number. Also marks the per-axis snap as a ceiling
and checks a rotated scaled monitor and a two-monitor file.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

2 files changed, 13 insertions, 2 deletions

diff --git a/desktop/modules/monitors/Mon.js b/desktop/modules/monitors/Mon.js
index 9b5e158..865e155 100644
--- a/desktop/modules/monitors/Mon.js
+++ b/desktop/modules/monitors/Mon.js
@@ -52,12 +52,14 @@ function draft(m) {
              position: m.x + "x" + m.y, x: m.x, y: m.y };
 }
 
-// Logical size: an odd transform is a quarter turn, scale divides.
+// Logical size: an odd transform is a quarter turn, scale divides. A scale
+// being typed ("", "1.") draws at 1 until it is a positive number.
 function size(mode, scale, transform) {
     const p = /^(\d+)x(\d+)/.exec(mode);
+    const k = +scale > 0 ? +scale : 1;
     let w = +p[1], h = +p[2];
     if (transform % 2) { const t = w; w = h; h = t; }
-    return { w: w / +scale, h: h / +scale };
+    return { w: w / k, h: h / k };
 }
 
 // The layout position: exact XxY, or where Hyprland last put an auto one.
@@ -90,6 +92,9 @@ function nearest(v, cands, t) {
 
 // r ({x, y, w, h}, logical) moved so an edge within t lies on an edge of one
 // of others: beside it, or aligned with it. Each axis on its own, rounded.
+// ponytail: an axis snaps to a monitor however far off it is on the other
+// axis, and overlaps are not refused; right for two monitors, check both
+// axes together if a third is added.
 function snap(r, others, t) {
     const xs = [], ys = [];
     for (const o of others) {
diff --git a/desktop/modules/monitors/test_mon.js b/desktop/modules/monitors/test_mon.js
index 6b12ee7..5d28ce4 100644
--- a/desktop/modules/monitors/test_mon.js
+++ b/desktop/modules/monitors/test_mon.js
@@ -40,6 +40,9 @@ assert.deepStrictEqual([d.mode, d.scale, d.transform, d.vrr, d.position, d.x, d.
 // Logical size: an odd transform swaps, scale divides.
 assert.deepStrictEqual(M.size("1920x1080@100.00", "1", 1), { w: 1080, h: 1920 });
 assert.deepStrictEqual(M.size("2560x1440@60.00", "1.25", 0), { w: 2048, h: 1152 });
+assert.deepStrictEqual(M.size("2560x1440@60.00", "2", 7), { w: 720, h: 1280 });
+// A scale mid-typing draws at 1 rather than Infinity or NaN.
+assert.deepStrictEqual(M.size("1920x1080@60.00", "", 0), { w: 1920, h: 1080 });
 
 // Exact positions parse, auto ones fall back to where Hyprland put it.
 assert.deepStrictEqual(M.xy({ position: "-1080x-960", x: 0, y: 0 }), { x: -1080, y: -960 });
@@ -55,6 +58,9 @@ assert.ok(M.lua(Object.assign({}, d, { vrr: true })).endsWith("transform = 1, vr
 const f = M.file([d]);
 assert.ok(f.startsWith("-- Monitors, written by the keystone settings window"));
 assert.ok(f.includes("-- DP-3: ASUS VG279Q3A\n" + M.lua(d) + "\n"));
+// Two monitors, in order, a blank line before each.
+const two = M.file([d, Object.assign({}, d, { name: "DP-1" })]);
+assert.ok(two.indexOf("-- DP-3") < two.indexOf("-- DP-1") && two.includes(M.lua(d) + "\n\n-- DP-1"));
 
 // Snapping: DP-1 is 2560x1080 at 0,-540. A 1080x1920 monitor dropped with
 // its right edge 30px short of DP-1's left edge snaps flush; 200px short